Thu·Feb 15, 2024Thursday·February 15, 2024

1. 01*

   The impact of CP-violating phases on DM observables in the cpMSSM

   Melissa van Beekveld🇳🇱 · Wim Beenakker🇳🇱 · Jochem Kip🇳🇱 · Marrit Schutten🇳🇱 · Dirren van Vlijmen🇳🇱

   In this paper we examine the effect of adding CP-violating phases to the pMSSM on the Dark-Matter (DM) direct-detection cross sections, the velocity-weighted annihilation cross section, and the DM relic density. We show that ${\phi }_{M_2}$ and ${\phi }_{\mu }$, the phases of the wino and higgsino mass parameters, are sufficiently constrained by electron electric-dipole-moment (EDM) measurements such that the allowed values of these phases are too small to influence these DM observables. Conversely, the phase of the bino-mass parameter ${\phi }_{M_1}$ and the phases associated with the trilinear couplings, ${\phi }_{A^t}$, ${\phi }_{A^b}$, and ${\phi }_{A^{\tau }}$, are barely constrained by EDM experiments. We find that these cpMSSM phases can have an important impact on the mentioned DM observables. This especially concerns pMSSM points that lie on the boundary of exclusion, as observables can be affected by cpMSSM phases to the extent that they are either pushed into the observable region, or outside the excluded region.

   hep-ph2 citations
2. 02*

   Implications of conservation laws and ergodicity for neutrino flavor instability

   Lucas Johns🇺🇸

   Collective neutrino flavor instabilities are believed to be prevalent in core-collapse supernovae and neutron star mergers. This work establishes two points related to instability, both in the spirit of developing a more fundamental understanding of collective flavor dynamics. First, a conservation law related to lepton number implies that spectral crossings are necessary for instability. Second, the most permissive application of the ergodic hypothesis to neutrino flavor evolution implies that spectral crossings are in fact sufficient for instability. We also discuss flavor thermalization and energy conservation in relation to ergodicity.

   hep-phastro-ph.HEPRD(2025)·13 citations
3. 03*

   Differential torsion sensor for direct detection of ultralight vector dark matter

   Ling Sun🇦🇺 · Bram J. J. Slagmolen🇦🇺 · Jiayi Qin🇦🇺

   Ultralight bosons with masses in the range from $\sim 10^{-22}$ eV/$c^2$ to $\sim 1$ eV/$c^2$, are well-motivated, wave-like dark matter candidates. Particles on the lower-mass end are less explored in experiments due to their vanishingly small mass and weak coupling to the Standard Model. We propose a sensor with dual torsion pendulums for the direct detection of U(1)${}_{B-L}$ gauge boson dark matter, which can achieve an enhanced differential torque sensitivity in a frequency band of $\sim 10^{-2}$-$10$ Hz due to its advantages in common-mode rejection and differential angular sensitivity. We describe the design of the differential torsion sensor and present the estimated sensitivity to an ultralight dark matter field coupled to baryon minus lepton ($B-L$) number, in a mass range of $\sim 10^{-17}$-$10^{-13}$ eV/$c^2$. Given a setup with meter-scale torsion pendulum beams and kg-scale test masses, the projected constraints on the coupling constant $g_{B-L}$ can reach $\sim 10^{-27}$ for a boson mass of $\sim 10^{-15}$ eV/$c^2$.

   hep-phastro-ph.COgr-qcPRD(2025)·10 citations
4. 04*

   Doubly heavy dibaryons as seen by string theory

   Oleg Andreev🇩🇪

   We propose the stringy description of the system consisting of two heavy and four light quarks in the case of two light flavors of equal mass. As an application, we consider the three low-lying Born-Oppenheimer potentials as a function of the heavy quark separation. Our analysis shows that the ground state potential is described in terms of both hadro-quarkonia and hadronic molecules. A connected string configuration makes the dominant contribution to the potential of an excited state at small separations, and for separations larger than $0.1\text{fm}$, it exhibits the diquark-diquark-diquark structure $[Qq][Qq][qq]$. For better understanding the quark organization inside the system, we introduce several critical separations related to the processes of string reconnection, breaking and junction annihilation. We also discuss the simplest string configurations including the five-string junctions and their implications for the system, in particular the emergence of composite quark objects different from diquarks and the process of junction fusion.

   hep-phhep-lathep-thnucl-thPRD(2024)·7 citations
5. 05*

   Thermodynamic properties and phase diagram of quark matter within non-extensive Polyakov chiral SU (3) quark mean field model

   Dhananjay Singh🇮🇳 · Arvind Kumar🇮🇳

   In the present work, we apply Tsallis non-extensive statistics to study the thermodynamic properties and phase diagram of quark matter in the Polyakov chiral SU(3) quark mean field model. Within this model, the properties of the quark matter are modified through the scalar fields $\sigma ,\zeta ,\delta ,\chi$, the vector fields $\omega ,\rho$, $\varphi$, and the Polyakov fields $\Phi$ and $\bar{\Phi }$ at finite temperature and chemical potential. Non-extensive effects have been introduced through a dimensionless parameter $q$ and the results are compared to the extensive case ($q\to 1$). In the non-extensive case, the exponential in the Fermi-Dirac (FD) function is modified to a $q$-exponential form. The influence of $q$ parameter on the thermodynamic properties: pressure, energy, and entropy density as well as trace anomaly is investigated. The speed of sound and specific heat with non-extensive effects is also studied. Furthermore, the effect of non-extensivity on the deconfinement phase transition as well as the chiral phase transition of $u,d,$ and $s$ quarks is explored. We found that the critical end point (CEP), which defines the point in the $(T-\mu )$ phase diagram where the order of the phase transition changes, shifts to a lower value of temperature, $T_{CEP}$, and a higher value of chemical potential, ${\mu }_{CEP}$, as the non-extensivity is increased, i.e., $q>$1.

   hep-phnucl-thCPC(2024)·6 citations
6. 06*

   Minijet quenching in non-equilibrium quark-gluon plasma

   Fabian Zhou🇩🇪 · Jasmine Brewer🇬🇧 · Aleksas Mazeliauskas🇩🇪

   We study the energy deposition and thermalisation of high-momentum on-shell partons (minijets) travelling through a non-equilibrium Quark-Gluon Plasma using QCD kinetic theory. For thermal backgrounds, we show that the parton energy first flows to the soft sector by collinear cascade and then isotropises via elastic scatterings. In contrast, the momentum deposition from a minijet reaches the equilibrium distribution directly. For expanding non-equilibrium QGP, we study the time for a minijet perturbation to lose memory of its initial conditions, namely, the hydrodynamisation time. We show that the minijet evolution scales well with the relaxation time ${\tau }_R\propto \eta /s/T(\tau )$, where $T(\tau )$ is the effective temperature and $\eta /s$ is the viscosity over entropy ratio.

   hep-phnucl-thJHEP(2024)·19 citations
7. 07*

   Exploring semi-inclusive two-nucleon emission in neutrino scattering: a factorized approximation approach

   V.L. Martinez-Consentino🇪🇸 · J.E. Amaro🇪🇸

   The semi-inclusive cross section of two-nucleon emission induced by neutrinos and antineutrinos is computed employing the relativistic mean field model of nuclear matter and the dynamics of meson exchange currents. Within this model we explore a factorization approximation based on the product of an integrated two-hole spectral function and a two-nucleon cross section averaged over hole pairs. We demonstrate that the integrated spectral function of the uncorrelated Fermi gas can be analytically computed, and we derive a simple fully relativistic formula for this function, showcasing its dependency solely on both missing momentum and missing energy. A prescription for the average momenta of the two holes in the factorized two-nucleon cross section is provided, assuming that these momenta are perpendicular to the missing momentum in the center-of-mass system. The validity of the factorized approach is assessed by comparing it with the unfactorized calculation. Our investigation includes the study of the semi-inclusive cross section integrated over the energy of one of the emitted nucleons and the cross section integrated over the emission angles of the two nucleons and the outgoing muon kinematics. A comparison is made with the pure phase-space model and other models from the literature. The results of this analysis offer valuable insights into the influence of the semi-inclusive hadronic tensor on the cross section, providing a deeper understanding of the underlying nuclear processes.

   hep-phnucl-thSymmetry(2024)·6 citations
8. 08*

   Tuning to the Edge of the Abyss in SU(5)

   Howard Georgi🇺🇸

   I show that if a dimensionless parameter is tuned to be close to the boundary of the positivity domain and symmetry breaking is driven by a cubic term in the Lagrangian, the scale of the physics of symmetry breaking in a quantum field theory as measured by the Higgs mass can be much greater than the dimensional scales in the classical Lagrangian. Radiative corrections produce large and physically important corrections, helping to stabilize the large VEV. The resulting picture contrasts sharply with the "modern" view of QFT as an effective field theory. I describe how this mechanism might produce the GUT scale in an SU(5) model in which the dimensional parameters in the Lagrangian are at the low scale.

   hep-phPLB(2024)·1 citation
9. 09*

   Sign of the $hZZ$ coupling and implication for new physics

   Dipankar Das🇮🇳 · Anirban Kundu🇮🇳 · Miguel Levy🇵🇹 · Anugrah M. Prasad🇮🇳 · Ipsita Saha🇮🇳 · Agnivo Sarkar🇮🇳

   The magnitudes of the couplings of the scalar resonance at 125 GeV with the SM particles are found to be consistent with those of the SM Higgs boson. However, the signs are not experimentally determined in most of the cases, a prime example being that with the $Z$-boson pair. In other words, ${\kappa }_Z^h$, the ratio of the couplings of the actual 125 GeV resonance with $ZZ$ and that of the SM Higgs boson with the same, is consistent with both $+1$ and $-1$, the latter being the `wrong-sign'. We argue that the wrong-sign $hZZ$ coupling will necessitate the intervention of new physics below $\mathcal{O}\left(620\right)$ GeV to safeguard the underlying theory from unitarity violation. The strength of the new nonstandard couplings can be derived from the unitarity sum rules, which are comparable to the SM-Higgs couplings in magnitude. Thus the strong limits from the direct searches at the LHC can help us rule out the existence of such nonstandard particles with unusually large couplings thereby disfavoring the possibility of a wrong-sign $hZZ$ coupling.

   hep-phhep-exPLB(2024)·4 citations
10. 10*

    Small instanton-induced flavor invariants and the axion potential

    Ravneet Bedi🇺🇸 · Tony Gherghetta🇺🇸 · Christophe Grojean🇩🇪 · Guilherme Guedes🇩🇪 · Jonathan Kley🇩🇪 · Pham Ngoc Hoa Vuong🇩🇪

    Small instantons which increase the axion mass due to an appropriate modification of QCD at a UV scale ${\Lambda }_{\mathrm{SI}}$, can also enhance the effect of CP-violating operators to shift the axion potential minimum by an amount, ${\theta }_{\mathrm{ind}}$, proportional to the flavorful couplings in the SMEFT. Since physical observables must be flavor basis independent, we construct a basis of determinant-like flavor invariants that arise from instanton calculations containing the effects of dimension-six CP-odd operators at the scale $\text{require}cancel{\Lambda }_{\cancel{\mathrm{CP}}}$. This new basis provides a more reliable estimate of the shift ${\theta }_{\mathrm{ind}}$, that is severely constrained by neutron electric dipole moment experiments. In particular, for the case of four-quark, semi-leptonic and gluon dipole operators, these invariants are then used to provide improved limits on the ratio of scales $\text{require}cancel{\Lambda }_{\mathrm{SI}}/{\Lambda }_{\cancel{\mathrm{CP}}}$ for different flavor scenarios. The CP-odd flavor invariants also provide a classification of the leading effects from Wilson coefficients, and as an example, we show that a semi-leptonic four-fermion operator is subdominant compared to the four-quark operators. More generally, the flavor invariants, together with an instanton NDA, can be used to more accurately estimate small instanton effects in the axion potential that arise from any SMEFT operator.

    hep-phJHEP(2024)·10 citations
11. 11*

    Parton cascades at DLA: the role of the evolution variable

    Carlota Andrés🇫🇷 · Liliana Apolinário🇵🇹 · Néstor Armesto🇪🇸 · André Cordeiro🇵🇹 · Fabio Dominguez🇪🇸 · José Guilherme Milhano🇵🇹

    The theoretical treatment of jet quenching lacks a full description of the interplay between vacuum-like emissions, usually formulated in momentum space, and medium induced ones that demand an interface with a space-time picture of the expanding medium and thus must be formulated in position space. In this work we build a toy Monte-Carlo parton shower ordered in formation time, virtual mass, and opening angle, which are equivalent at leading logarithmic accuracy. Aiming to explore a link with jet substructure, we compute the Lund plane distributions for the different ordering prescriptions. Further, we investigate the sensitivity of ordering prescriptions to medium effects by counting the number of events eliminated by a decoherence condition.

    hep-phEPJ Web Conf.(2024)·0 citations
12. 12*

    Bubble Misalignment Mechanism for Axions

    Junseok Lee🇯🇵 · Kai Murai🇯🇵 · Fuminobu Takahashi🇯🇵 · Wen Yin🇯🇵

    We study the dynamics of axions at first-order phase transitions in non-Abelian gauge theories. When the duration of the phase transition is short compared to the timescale of the axion oscillations, the axion dynamics is similar to the trapped misalignment mechanism. On the other hand, if this is not the case, the axions are initially expelled from the inside of the bubbles, generating axion waves on the outside. Analogous to the Fermi acceleration, these axions gain energy by repeatedly scattering off the bubble walls. Once they acquire enough energy, they can enter the bubbles. The novel ``bubble misalignment mechanism'' can significantly enhance the axion abundance, compared to models where the axion mass is either constant or varies continuously as a function of temperature. The increase in axion abundance depends on the axion mass, the duration of the phase transition, and the bubble wall velocity. This mechanism results in a spatially inhomogeneous distribution of axions, which could lead to the formation of axion miniclusters. It has potential implications for the formation of oscillons/I-balls, axion warm dark matter, cosmic birefringence, and the production of dark photons.

    hep-phastro-ph.COJCAP(2024)·19 citations
13. 13*

    Exploring the Flavor Symmetry Landscape

    Alfredo Glioti🇫🇷 · Riccardo Rattazzi🇨🇭 · Lorenzo Ricci🇺🇸 · Luca Vecchi🇮🇹

    We explore flavor dynamics in the broad scenario of a strongly interacting light Higgs (SILH). Our study focuses on the mechanism of partial fermion compositeness, but is otherwise as systematic as possible. Concretely, we classify the options for the underlying flavor (and CP) symmetries, which are necessary in order to bring this scenario safely within the range of present or future explorations. Our main goal in this context is to provide a practical map between the space of hypotheses (the models) and the experimental ground that will be explored in the medium and long term, in both indirect and direct searches, in practice at HL-LHC and Belle II, in EDM searches and eventually at FCC-hh. Our study encompasses scenarios with the maximal possible flavor symmetry, corresponding to minimal flavor violation (MFV), scenarios with no symmetry, corresponding to the so-called flavor anarchy, and various intermediate cases that complete the picture. One main result is that the scenarios that allow for the lowest new physics scale have intermediate flavor symmetry rather than the maximal symmetry of MFV models. Such optimal models are rather resilient to indirect exploration via flavor and CP violating observables, and can only be satisfactorily explored at a future high-energy collider. On the other hand, the next two decades of indirect exploration will significantly stress the parameter space of a large swath of less optimal but more generic models up to mass scales competing with those of the FCC-hh.

    hep-phhep-exhep-thSciPost Phys.(2025)·35 citations
14. 14*

    Deconstructing flavor anomalously

    Javier Fuentes-Martín🇪🇸 · Javier M. Lizana🇨🇭

    Flavor deconstruction refers to ultraviolet completions of the Standard Model where the gauge group is split into multiple factors under which fermions transform non-universally. We propose a mechanism for charging same-family fermions into different factors of a deconstructed gauge theory in a way that gauge anomalies are avoided. The mechanism relies in the inclusion of a strongly-coupled sector, responsible of both anomaly cancellation and the breaking of the non-universal gauge symmetry. As an application, we propose different flavor deconstructions of the Standard Model that, instead of complete families, uniquely identify specific third-family fermions. All these deconstructions allow for a new physics scale that can be as low as few TeV and provide an excellent starting point for the explanation of the Standard Model flavor hierarchies.

    hep-phhep-thJHEP(2024)·27 citations
15. 15*

    A Language Model for Particle Tracking

    Andris Huang🇺🇸 · Yash Melkani · Paolo Calafiura🇺🇸 · Alina Lazar🇺🇸 · Daniel Thomas Murnane · Minh-Tuan Pham🇺🇸 · Xiangyang Ju🇺🇸

    Particle tracking is crucial for almost all physics analysis programs at the Large Hadron Collider. Deep learning models are pervasively used in particle tracking related tasks. However, the current practice is to design and train one deep learning model for one task with supervised learning techniques. The trained models work well for tasks they are trained on but show no or little generalization capabilities. We propose to unify these models with a language model. In this paper, we present a tokenized detector representation that allows us to train a BERT model for particle tracking. The trained BERT model, namely TrackingBERT, offers latent detector module embedding that can be used for other tasks. This work represents the first step towards developing a foundational model for particle detector understanding.

    hep-phcs.LGhep-ex11 citations
16. 16*

    Chromo-natural warm inflation

    Ann Mukuno🇯🇵 · Jiro Soda🇯🇵

    Chromo-natural inflation is a model where non-abelian gauge fields are sustained by the coupling of the axion with the gauge field through the Chern-Simons term. While minimal warm inflation is a model where the axion produces a thermal bath of non-abelian gauge particles through the Chern-Simons term. Since both axion inflation models are based on the same action, a natural question is if those are compatible or not. We study axion inflation with the Chern-Simons term and find that chromo-natural inflation can accommodate radiation with a temperature much larger than the Hubble parameter during inflation, which is a characteristic feature of warm inflation. Thus, we conclude that chromo-natural warm inflation exists, which must have phenomenologically interesting consequences.

    ↳ hep-thhep-phPRD(2024)·10 citations
17. 17*

    Probing the signature of axions through the quasinormal modes of black holes

    Antonio De Felice🇯🇵 · Shinji Tsujikawa🇯🇵

    The axion-photon coupling allows the existence of a magnetically and electrically charged black hole (BH) solution endowed with a pseudo-scalar hair. For the Reissner-Nordstrom BH with a given total charge and mass, it is known that the quasinormal modes (QNMs) are independent of the mixture between the magnetic and electric charges due to the presence of electric-magnetic duality. We show that the BH with an axion hair breaks this degeneracy by realizing nontrivial QNMs that depend on the ratio between the magnetic and total charges. Thus, the upcoming observations of BH QNMs through gravitational waves offer an exciting possibility for probing the existence of both magnetic monopoles and the axion coupled to photons.

    ↳ gr-qcastro-ph.COhep-phhep-thPLB(2024)·9 citations
18. 18*

    Lattice calculation of electromagnetic corrections to $K\ell 3$ decay

    Norman H. Christ🇺🇸 · Xu Feng🇨🇳 · Luchang Jin🇺🇸 · Christopher T. Sachrajda🇬🇧 · Tianle Wang🇺🇸

    We describe a first-principles method to apply lattice QCD to compute the order ${\alpha }_{\mathrm{EM}}$ corrections to $K\to \pi \ell {\nu }_{\ell }$ decay. This method formulates the calculation in infinite volume with the conventional infinite-volume, continuum treatment of QED. Infinite volume reconstruction is used to replace the QCD components of the calculation with finite-volume amplitudes which can be computed in Euclidean space using lattice QCD, introducing finite-volume errors which vanish exponentially as the volume used in the QCD calculation is increased. This approach has also been described in an appendix to the recent paper: arXiv:2304.08026.

    ↳ hep-lathep-phPoS(2024)·4 citations
19. 19*

    Complete complementarity relations in tree level QED processes

    Massimo Blasone🇮🇹 · Silvio De Siena🇮🇹 · Gaetano Lambiase🇮🇹 · Cristina Matrella🇮🇹 · Bruno Micciola🇮🇹

    We exploit the complete complementarity relations (CCR) to fully characterize various aspects of quantumness in QED scattering processes at tree level. As a paradigmatic example, we consider Bhabha scattering in two different configurations: in the first case, the initial state is factorized in the spin and we study the generation of entanglement due to the scattering. Then we consider the most general case in which the initial state can be entangled: we find that the scattering generates and distributes quantum information in a non-trivial way among the spin degrees of freedom of the particles, with CCR relations being preserved. An important outcome of our analysis is that maximal entanglement is conserved in the scattering process involving only fermions as input and output states, with a more complex situation if photons are present.

    ↳ quant-phhep-phhep-thPRD(2025)·27 citations
20. 20*

    Neutrino flavor transformation with moments: application to fast flavor instabilities in neutron star mergers

    Julien Froustey🇺🇸 · Sherwood Richers🇺🇸 · Evan Grohs🇺🇸 · Samuel D. Flynn🇺🇸 · Francois Foucart🇺🇸 · James P. Kneller🇺🇸 · Gail C. McLaughlin🇺🇸

    Neutrino evolution, of great importance in environments such as neutron star mergers (NSMs) because of their impact on explosive nucleosynthesis, is still poorly understood due to the high complexity and variety of possible flavor conversion mechanisms. In this study, we focus on so-called "fast flavor oscillations", which can occur on timescales of nanoseconds and are connected to the existence of a crossing between the angular distributions of electron (anti)neutrinos. Based on the neutrino radiation field drawn from a three dimensional neutron star merger simulation, we use an extension of the two-moment formalism of neutrino quantum kinetics, and perform a linear stability analysis to determine the characteristics of fast flavor instabilities across the simulation. We compare the results to local (centimeter-scale) three-dimensional two-flavor simulations using either a moment method or a particle-in-cell architecture. We get generally good agreement in the instability growth rate and typical instability lengthscale, although the imperfections of the closure used in moment methods remain to be better understood.

    ↳ astro-ph.HEhep-phPoS(2024)·4 citations
21. 21*

    Lattice $B$-field correlators for heavy quarks

    Luis Altenkort🇩🇪 · David de la Cruz🇩🇪 · Olaf Kaczmarek🇩🇪 · Guy D. Moore🇩🇪 · Hai-Tao Shu🇺🇸

    We analyze the color-magnetic (or "$B$") field two-point function that encodes the finite-mass correction to the heavy quark momentum diffusion coefficient. The simulations are done on fine isotropic lattices in the quenched approximation at $1.5T_c$, using a range of gradient flow times for noise suppression and operator renormalization. The continuum extrapolation is performed at fixed flow time followed by a second extrapolation to zero flow time. Perturbative calculations to next-to-leading order of this correlation function, matching gradient-flowed correlators to MS-bar, are used to resolve nontrivial renormalization issues. We perform a spectral reconstruction based on perturbative model fits to estimate the coefficient ${\kappa }_B$ of the finite-mass correction to the heavy quark momentum diffusion coefficient. The approach we present here yields high-precision data for the correlator with all renormalization issues incorporated at next-to-leading order, and is also applicable for actions with dynamical fermions.

    ↳ hep-lathep-phPRD(2024)·13 citations
22. 22*

    Mass Beyond Measure: Eccentric Searches for Black Hole Populations

    Nicholas DePorzio🇺🇸 · Lisa Randall🇺🇸 · Zhong-Zhi Xianyu🇨🇳

    Stellar mass binary black holes of unknown formation mechanism have been observed, motivating new methods for distinguishing distinct black hole populations. This work explores how the orbital eccentricity of stellar mass binary black holes is a viable conduit for making such distinctions. Four different production mechanisms, and their corresponding eccentricity distributions, are studied in the context of an experimental landscape composed of mHz (LISA), dHz (DECIGO), and Hz (LIGO) range gravitational wave detectors. We expand on prior work considering these effects at fixed population eccentricity. We show that a strong signal corresponding to subsets of eccentric populations is effectively hidden from the mHz and dHz range gravitational wave detectors without the incorporation of high eccentricity waveform templates. Even with sufficiently large eccentricity templates, we find dHz range experiments with a LISA-like level of sensitivity are unlikely to aid in distinguishing different populations. We consider the degree to which a mHz range detector like LISA can differentiate among black hole populations independently and in concert with follow-up merger detection for binaries coalescing within a 10 year period. We find that mHz range detectors, with only $e<0.01$ (nearly circular) sensitivity, can successfully discern eccentric sub-populations except when attempting to distinguish very low eccentricity distributions. In these cases where $e<0.01$ sensitivity is insufficient, we find that the increase in event counts resulting from $e<0.1$ sensitivity provides a statistically significant signal for discerning even these low eccentricity sub-populations. While improvements offered by $e<0.1$ sensitivity can be generally increased by $\mathcal{O}(1)$ factors with $e<0.4$ sensitivity, going beyond this in eccentricity sensitivity provides negligible enhancement.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-ph6 citations
23. 23*

    Nonmonotonic specific entropy on the transition line near the QCD critical point

    Maneesha Sushama Pradeep🇺🇸 · Noriyuki Sogabe🇺🇸 · Mikhail Stephanov🇺🇸 · Ho-Ung Yee🇺🇸

    We investigate the effect of the quantum chromodynamics (QCD) critical point on the isentropic trajectories in the QCD phase diagram. We point out that the universality of the critical equation of state and the third law of thermodynamics require the specific entropy (per baryon) along the coexistence (first-order transition) line to be nonmonotonic at least on one side of that line. Specifically, a maximum must occur. We show how the location of the maximum relative to the QCD critical point depends on the parameters of the critical equation of state commonly used in the literature. We then examine how the isentropic trajectories followed by adiabatically expanding heavy-ion collision fireballs behave near the critical point. We find that a crucial role is played by the sign of the isochoric temperature derivative of pressure at the critical point; this sign determines on which side of the coexistence curve the specific entropy must be nonmonotonic (i.e., has a maximum). We classify different scenarios of the adiabatic expansion that arise depending on the value of the discriminant parameter and the proximity of the trajectory to the critical point.

    ↳ nucl-thcond-mat.stat-mechhep-lathep-phPRC(2024)·17 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.